This invention relates generally to water heaters, and, more particularly, to an insulated supplemental water tank for water heater systems.
A typical hot water heater of the type used in a home basically consists of a water tank, usually insulated with fiberglass or foam insulation, with a heat source positioned in its bottom end. The heat source for the water heater may be a combustible fuel such as natural gas that is burned in a combustion chamber located beneath the tank. Alternatively, the heat source may be an electric heating element positioned in the bottom of the tank.
The water heater is connected to a water source, such as a city water system, so that water is introduced into the tank through its lower portion. As the water is heated by the heat source, it becomes less dense, thereby rising to the top of the tank. Heated water from the top of the water heater tank is drawn off and supplied to use points in the home, such as faucets, shower heads, dishwashers and laundry machines, via the home hot water system.
A disadvantage of such an arrangement, however, is that during periods of high hot water usage, the temperature of the water may be inconsistent as water is drawn off of the top of the water heater tank faster than the heat source may heat it. In extreme cases, all of the hot water may be used so that the water heater must be given time to “catch up” before hot water is once again available. This may be very problematic for large families or homes with a large number of guests.
One solution to such difficulties is to increase the size of the water heater tank and heat source so that the water heater has greater capacity. A disadvantage of this approach, however, is higher energy usage by the larger heat source. In addition, means of access to the room in which the water heater is installed is often limited in size. Homes, buildings and rooms typically have doors of standard width, commonly 32, 36, 48 or 72 inches, and this limits the size, and thus the capacity of water heater that may be installed. Larger capacity water heaters also cost more and thus are expensive to replace.
An alternative approach to providing additional capacity is to multiply the number of water heaters. For example, one could obtain 100 gallon capacity by providing two complete 50 gallon water heaters. This solution is undesirable in that such an approach nearly doubles the cost and maintenance requirements of the system. In addition, duplicative controls are required which further adds to the cost of installation and maintenance.
Systems that provide smaller, supplemental water heaters positioned at the point of use to provide instant hot water are well known in the art. Such systems are illustrated in U.S. Pat. No. 1,555,338 to Vaughan, U.S. Pat. No. 2,969,451 to Logan and U.S. Pat. No. 4,680,446 to Post. Such supplemental water heaters are positioned near faucets, such as under a kitchen sink, or close to other points of use. While the supplemental water heater tanks are insulated, the efficiency of the insulation is not sufficient to keep the water warm without the use of an electric heat source positioned within the supplemental water heater tank. The additional heat source equates to additional energy usage and increased maintenance frequency and cost. Such systems also do not significantly increase the hot water capacity of the system given the limited space provided by the point of use installation.
Accordingly, it is an object of the present invention to provide a water heater system that provides increased hot water capacity.
It is another object of the present invention to provide a water heater system that provides greater consistency in terms of water temperature at points of use.
It is another object of the present invention to provide a water heater system that provides increased capacity without large additional energy usage.
It is still another object of the present invention to provide a water heater system that provides increased capacity with minimal additional complexity.
It is still another object of the present invention to provide a water heater system that provides additional capacity with minimal additional maintenance requirements.